Kennedy Space Center, Oct. 18, 1989: A roar shakes the ground as Space Shuttle
Atlantis climbs into the sky. The Galileo spacecraft rides in the payload bay, ready to begin a long
journey into the realm of the outer planets. Its mission is to study Jupiter and its moons in more
detail than any previous spacecraft.

The spacecraft is named in honor of the first modern astronomer --- Galileo Galilei. He made
the first observations of the heavens using a telescope in 1610.

A montage of Jupiter and the Galilean satellites.

What compels us to explore Jupiter?
The giant colorful planet holds clues to help us understand how the Sun and planets formed more
than 4.5 billion years ago. One of
Jupiter's moons
has active volcanoes and others have strange icy terrain. How does these strange worlds compare
with Earth?

Galileo arrived at Jupiter in December 1995. As fascinating data poured in from the orbiting
spacecraft and its atmospheric probe, we knew it was just the beginning.